@tricia @ajlanes I'm a climber too, although I can't do it much any more because I have Dupuytrens.
Climbing the mast is easy. Friction knot with a mooring line round the mast, make a foot loop, main halyard tied to belay loop, have someone on the winch. You lift yourself up, they take in the slack. Repeat.
The issue is that you're not standing on anything, so even in the comfiest of harnesses, I find my legs go unpleasantly numb quite quickly. If you were hanging on a rock face, unless it was severely overhanging, you can usually take SOME weight on your legs, but try with the mast and you'll just pirouette around it.
The swaying you get used to. Worst bit is when some prick in a gas guzzler does a close pass and kicks up a load of wake. Then it gets interesting.